Sheet Membrane
TPO | PVC | Reinforced Modified Bitumen (Torch-On)
Whether your project requires TPO, PVC, or RMB (Reinforced Modified Bitumen), commonly known as torch-on membrane, Gunac | Waterproofing Specialists delivers professional sheet membrane waterproofing solutions for commercial, industrial, and large-scale residential buildings across New Zealand.
Our experienced membrane technicians are highly trained in the installation of both double-layer and single-layer premanufactured sheet systems, ensuring long-term durability, compliance, and watertight performance.
What Is Sheet Membrane Waterproofing?
Sheet membranes are pre-manufactured waterproofing systems designed to create a continuous, fully bonded barrier that prevents water ingress. They are widely specified for both above-ground and below-ground applications due to their proven reliability and longevity.
Double-Layer Membranes
Typically consist of torch-applied bitumen-based systems (RMB).
Installed using a primer followed by a flame-applied base sheet
A second cap sheet is applied and staggered in a “brick bond” pattern
Creates a robust, multi-layer waterproofing system
Ideal for high-performance roofing and deck applications
The staggered laps significantly reduce the risk of water tracking into the substrate, enhancing long-term protection.
Single-Layer Membranes (TPO & PVC)
A cold-applied system installed using contact adhesives or self-adhesive backing.
Seams are heat-welded using controlled hot air
Provides consistent, uniform joins
Suitable for commercial flat roofs and lightweight structures
Cleaner installation method with no open flame required
Suitable Applications
Our teams install sheet membrane systems across a wide range of building types and substrates.
Above-ground applications include:
Flat roofs
Decks and podium areas
Box gutters
Warm roof systems
Below-ground applications include:
Retaining walls
Concrete slabs
Basement structures (where specified)
Sheet membranes can be installed over:
Plywood substrates
Concrete
Insulated warm roof systems
We can also specify trafficable membrane systems for decks and apply suitable variations for planter boxes where required.
Technical Oversight & Cost-Effective Methodology
Our qualified Quantity Surveyors and project teams tailor each waterproofing specification to suit your building’s design, usage requirements, and budget. We work closely with system suppliers to ensure compliance with manufacturer specifications and building code requirements.
The result is a cost-effective waterproofing solution without compromising on durability or performance.
Warranty & Assurance
Our qualified Quantity Surveyors and project teams tailor each waterproofina
With expert installation and adherence to supplier specifications, we provide:
5-year workmanship warranty
Up to 20-year product warranty (subject to specification and supplier approval)
Why Choose Gunac for Sheet Membrane Waterproofing?
Specialist waterproofing expertise
Experienced, certified membrane applicators
Compliance-focused methodology
Proven performance in commercial environments
Integrated project delivery through Access Partners in Property
When long-term waterproofing performance matters, sheet membrane systems installed correctly the first time make all the difference.
Some Of Our Projects
Get In Touch With Our Team
As a client, you will be satisfied knowing your project will be led and completed by a qualified and certified team. Our team include Project Managers and Quantity Surveyors who bring international experience to offer solutions for you.